3.x: Workaround flakyness of multiThreadedWithNPE* tests (#6953)

* 3.x: Workaround flakyness of multiThreadedWithNPE* tests

* Do not run the original test

Author: akarnokd

src/test/java/io/reactivex/rxjava3/internal/operators/flowable/FlowableSerializeTest.java

@@ -79,7 +79,22 @@ public void multiThreadedBasic() {
     }
 
     @Test
-    public void multiThreadedWithNPE() {
+    public void multiThreadedWithNPEFlaky() throws InterruptedException {
+        int max = 9;
+        for (int i = 0; i <= max; i++) {
+            try {
+                multiThreadedWithNPE();
+                return;
+            } catch (AssertionError ex) {
+                if (i == max) {
+                    throw ex;
+                }
+            }
+            Thread.sleep((long)(1000 * Math.random() + 100));
+        }
+    }
+
+    void multiThreadedWithNPE() {
         TestMultiThreadedObservable onSubscribe = new TestMultiThreadedObservable("one", "two", "three", null);
         Flowable<String> w = Flowable.unsafeCreate(onSubscribe);
 
@@ -108,7 +123,22 @@ public void multiThreadedWithNPE() {
     }
 
     @Test
-    public void multiThreadedWithNPEinMiddle() {
+    public void multiThreadedWithNPEinMiddleFlaky() throws InterruptedException {
+        int max = 9;
+        for (int i = 0; i <= max; i++) {
+            try {
+                multiThreadedWithNPEinMiddle();
+                return;
+            } catch (AssertionError ex) {
+                if (i == max) {
+                    throw ex;
+                }
+            }
+            Thread.sleep((long)(1000 * Math.random() + 100));
+        }
+    }
+
+    void multiThreadedWithNPEinMiddle() {
         boolean lessThan9 = false;
         for (int i = 0; i < 3; i++) {
             TestMultiThreadedObservable onSubscribe = new TestMultiThreadedObservable("one", "two", "three", null, "four", "five", "six", "seven", "eight", "nine");

src/test/java/io/reactivex/rxjava3/internal/operators/observable/ObservableSerializeTest.java

@@ -78,7 +78,22 @@ public void multiThreadedBasic() {
     }
 
     @Test
-    public void multiThreadedWithNPE() {
+    public void multiThreadedWithNPEFlaky() throws InterruptedException {
+        int max = 9;
+        for (int i = 0; i <= max; i++) {
+            try {
+                multiThreadedWithNPE();
+                return;
+            } catch (AssertionError ex) {
+                if (i == max) {
+                    throw ex;
+                }
+            }
+            Thread.sleep((long)(1000 * Math.random() + 100));
+        }
+    }
+
+    void multiThreadedWithNPE() {
         TestMultiThreadedObservable onSubscribe = new TestMultiThreadedObservable("one", "two", "three", null);
         Observable<String> w = Observable.unsafeCreate(onSubscribe);
 
@@ -107,7 +122,22 @@ public void multiThreadedWithNPE() {
     }
 
     @Test
-    public void multiThreadedWithNPEinMiddle() {
+    public void multiThreadedWithNPEinMiddleFlaky() throws InterruptedException {
+        int max = 9;
+        for (int i = 0; i <= max; i++) {
+            try {
+                multiThreadedWithNPEinMiddle();
+                return;
+            } catch (AssertionError ex) {
+                if (i == max) {
+                    throw ex;
+                }
+            }
+            Thread.sleep((long)(1000 * Math.random() + 100));
+        }
+    }
+
+    void multiThreadedWithNPEinMiddle() {
         boolean lessThan9 = false;
         for (int i = 0; i < 3; i++) {
             TestMultiThreadedObservable onSubscribe = new TestMultiThreadedObservable("one", "two", "three", null, "four", "five", "six", "seven", "eight", "nine");